1. Field of the Invention
The present invention relates to an image reading apparatus and a copying apparatus.
2. Related Background Arts
Conventionally, there has been proposed a technique wherein a specific mark is printed using a fluorescent ink which excites a visible image upon radiation of, e.g., ultraviolet rays onto a specific image, and the specific image is discriminated based on the presence/absence of excited light upon irradiation with ultraviolet rays so as to discriminate whether an original bears the specific image.
When the above-mentioned technique is applied to an image reading apparatus, how precisely the specific image is discriminated, as well as normal original reading, and how simple the discrimination arrangement is, are serious problems.
More specifically, when marks are written on an original using, e.g., a fluorescent pen,.a discrimination error may occur, and it is difficult to improve discrimination precision.
When the above-mentioned technique is applied to a copying machine, it is difficult to detect a specific original which is located at an arbitrary angle with respect to an arbitrary position on an original table of the copying machine, and hence, it is difficult to prevent illicit copying operation of the specific original.
Even when line image information or a color tone of an original is detected, some normal originals may exhibit equivalent characteristics to those of a specific original, and a normal original may be erroneously determined to be a copy-inhibited original.